4,551 research outputs found
Reactive transport modeling of fluid-rock interactions associated with carbonate diagenesis and implications for reservoir quality prediction
Die Diageneseforschung ist die Grundlage fĂĽr die Charakterisierung und Exploration von
Kohlenwasserstofflagerstätten. Die reaktive Transportmodellierung (RTM) ist ein neuer
Ansatz für die Diageneseforschung mit der einzigartigen Fähigkeit zur Quantifizierung und
Vorwärtsmodellierung der gekoppelten thermo-hydrochemischen Prozesse der Diagenese.
Diese Arbeit untersucht die beiden wichtigsten Fluid-Gesteins-Wechselwirkungen in
Karbonatgesteinen, d. h. Dolomitisierung und Verkarstung, basierend auf generischen
Modellanalysen und einer Fallstudie im Ordos-Becken, China.
Bei der Refluxdolomitisierung werden zunehmender Dolomit, abnehmender Kalzit und
dynamische Gipsausfällung/-auflösung beobachtet. Höherer Solesalzgehalt, Temperatur und
reaktive Oberfläche tragen zu einem höheren Dolomitisierungsgrad bei. Die Porosität-Permeabilität des Gesteins wird kollektiv durch die Porenzunahme durch Dolomitisierung und
die Porenfüllung durch Gipsausfällung gesteuert. Bei der eogenetischen Verkarstung gibt es
einen abnehmenden Trend bei der Karbonatauflösung und Gesteinsporosität. Die Dauer der
subaerialen Exposition und das Klima bestimmen maĂźgeblich die vom Karst beeinflusste
Tiefe und Porositätszunahme. Die atmosphärische pCO2-Konzentration hat einen geringen
Einfluss auf die Karstausdehnung, während sie die Auflösungsgeschwindigkeit beeinflusst.
Eine integrierte geologische und RTM-Studie zeigt, dass die Hauptporositäten des Reservoirs
der Ordovizium-Majiagou-Formation im Ordos-Becken während der frühen Diagenese
entstanden sind. Die mehrstufige Refluxdolomitisierung fand in der eingeschränkten
Verdunstungsumgebung statt, was zu einem maximalen Porositätszuwachs von 7,3% des
Lagunenfazies-Mikrits führte. Der eogenetische Karst entwickelte sich hauptsächlich in
Schwarmfazies-Grainstein mit einer Dauer der subaerialen Exposition von 30–110 ka und
einer Porositätszunahme von 1,5–6,7% (durchschnittlich 3,1%). Die weitere Exploration des
Reservoirs sollte sich auf die Sedimentumgebung und die Paläogeographie konzentrieren, die
die Dolomitisierung und Verkarstung kontrollieren. Die Ergebnisse sind hilfreich, um die
räumlich-zeitliche Verteilung und Koevolution von Diagenese und Mineralporosität besser zu
verstehen und die Unsicherheit der Vorhersage der Reservoirqualität zu verringern.Diagenesis research is the foundation of hydrocarbon reservoir characterization and
exploration. Reactive transport modeling (RTM) is an emerging approach for diagenesis
research, with the unique capability of quantification and forward modeling of the coupled
thermo-hydro-chemical processes of diagenesis. This thesis investigates the two most
important fluid-rock interactions in carbonate rocks, i.e., dolomitization and karstification,
based on generic model analyses and a case study in the Ordos Basin, China.
For reflux dolomitization, increasing dolomite, decreasing calcite and dynamic gypsum
precipitation/dissolution are observed. Higher brine salinity, temperature and reactive surface
area contribute to a higher degree of dolomitization. The rock porosity-permeability is
collectively controlled by pore-increment via dolomitization and pore-infill by gypsum
precipitation. For eogenetic karstification, there is a downward decreasing trend in carbonate
dissolution and rock porosity. The duration of subaerial exposure and climate significantly
determine the karst-affected depth and porosity increment. The atmospheric pCO2
concentration has a minor impact on the extent of karst, while it affects the dissolution rate.
Integrated geological and RTM study shows that the major porosities of the Ordovician
Majiagou Formation reservoir in the Ordos Basin were formed during early diagenesis. The
multistage reflux dolomitization occurred in the restricted-evaporative environment, giving
rise to a maximum 7.3% porosity increment of lagoon-facies micrite. The eogenetic karst
developed mainly in shoal-facies grainstone, with the duration of subaerial exposure of 30–
110 ka and porosity increments of 1.5%–6.7% (average 3.1%). Further exploration of the
reservoir should focus on sedimentary environment and paleogeography which control
dolomitization and karstification. The results are helpful to better understand the spatial-temporal distribution and co-evolution of diagenesis and mineral-porosity, and to reduce the
uncertainty of reservoir quality prediction
MicroRNA-124 enhances response to radiotherapy in human epidermal growth factor receptor 2-positive breast cancer cells by targeting signal transducer and activator of transcription 3
Aim To determine whether microRNA (miR)-124 enhances
the response to radiotherapy in human epidermal growth
factor receptor 2 (HER2)-positive breast cancer cells by targeting
signal transducer and activator of transcription 3
(Stat3).
Methods miR-29b expression was measured in 80 pairs of
breast tumor samples and adjacent normal tissues collected
between January 2013 and July 2014. Activity changes
of 50 canonical signaling pathways upon miR-124 overexpression
were determined using Cignal Signal Transduction
Reporter Array. Target gene of miR-124 was determined
using Targetscan and validated by Western blotting
and dual-luciferase assay. Cell death rate was assessed by
propidium iodide (PI)/Annexin V staining followed by flow
cytometry analysis. Stat3 and miR-124 expression was further
measured in 10 relapsed (non-responder) and 10 recurrence-
free HER2-positive breast cancer patients.
Results MiR-124 expression was down-regulated in HER2
positive breast cancers compared with normal tissues, and
was negatively associated with tumor size. MiR-124 overexpression
in HER2 positive breast cancer cell line SKBR3
significantly reduced the activity of Stat3 signaling pathway
compared with control transfection (P < 0.001). Bioinformatic
prediction and function assay suggested that
miR-124 directly targeted Stat3, which is a key regulator of
HER2 expression. MiR-124 overexpression down-regulated
Stat3 and potently enhanced cell death upon irradiation.
Consistently, chemical inhibitor of Stat3 also sensitized
HER2-positive breast cancer cells to irradiation. Moreover,
increased Stat3 expression and reduced miR-124 expression
were associated with a poor response to radiotherapy
in HER2-positive breast cancers.
Conclusions Weak miR-124 expression might enhance
Stat3 expression and radiotherapy resistance in HER2-positive
breast cancer cells
MiR-140-5p inhibits morphine tolerance in rats by targeting TLR4
Purpose: To determine the influence of miR-140-5p on morphine tolerance in rats.Methods: Sprague-Dawley (SD) rats were randomly divided into morphine tolerance (MT) and saline control (NS) groups, respectively. Rats in MT group were injected with 10 ÎĽL (10 ÎĽg) morphine twice daily for seven consecutive days while those in NS group were administered the equivalent volume of normal saline. The maximum effect of morphine (MPE) was computed from tail-flick test results. MiR-140-5p mimics and toll-like receptor 4 (TLR4) lentivirus were transfected separately or co-transfected into model rats. MiR-140-5p and TLR4 expression were determined by quantitative real-time polymerase chain reaction (RT-qPCR) or western blotting. Dual-luciferase reporter assay was used to verify the target relationship between miR-140-5p and TLR4.Results: The expression of miR-140-5p was decreased, while the expression of TLR4 increased in morphine-tolerant rats (p < 0.05). TLR4 was a target of miR-140-5p. At 24 and 48 h after injection, MPE clearly increased and TLR4 expression was reduced under miR-140-5p overexpression or TLR4 knockdown (p < 0.05). Moreover, there were no significant changes in MPE or levels of TLR4 when miR-140-5p and TLR4 were co-transfected into morphine-tolerant rats.Conclusion: MiR-140-5p inhibits morphine resistance in rats via targeted regulation of TLR4 expression. These provide a theoretical basis for the clinical management of morphine tolerance
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